The present invention relates to a side airbag apparatus that protects an occupant seated in a vehicle seat from an impact by deploying and inflating an airbag on a side of the occupant when the impact is applied to a vehicle.
A side airbag apparatus having an airbag and an inflator is widely known for protecting an occupant from an impact when the impact is applied to a car from a side to a car seat in which the occupant is seated, for example, due to a side collision. The airbag and the inflator are incorporated in the seat back of a car seat.
Japanese Laid-Open Patent Publication No. 9-240413 discloses a side airbag structure for a car seat, which includes a storage portion in a side portion of a seat back. An airbag is folded to be in a storage form. The airbag in the storage form is stored in the storage portion with an inflator and fixed to a seat frame. A cover with a hinge portion is provided on a side of the seat back to cover the storage portion. The storage portion also contains a guide piece, which is located forward of the airbag in the storage form and extends while being inclined forward.
In the side airbag structure, when an impact is applied from the side to a body side portion of the car, for example, to a side door, the inflator supplies inflation gas to the airbag. The inflation gas deploys and inflates the airbag, which in turn pushes the cover. The push displaces the cover sideways from the car seat with the hinge portion functioning as the pivot, thereby opening the storage portion. With a part (the part fixed to the seat frame) remaining in the storage portion, the airbag is deployed and inflated diagonally forward and sideways, that is, in a direction defined by the guide piece through the clearance between the guide piece and the cover. Thereafter, the airbag is deployed and inflated between the occupant and the body side portion, which is being deformed inward. The airbag restrains the occupant and reduces the impact that is transmitted from the side to the occupant through the body side portion.
In a car equipped with the above described side airbag structure mounted in the seat, the airbag is deployed and inflated in a narrow clearance between the seat back and the body side portion (for example, a side door). Further, when receiving an impact, the body side portion is displaced inward, which further narrows the clearance. To deploy and inflate an airbag in such a narrow clearance to restrain the occupant, it is required that the cover be quickly displaced to open the storage portion, thereby allowing the airbag to be quickly deployed and inflated beside the occupant. However, the side airbag apparatus of Japanese Laid-Open Patent Publication No. 9-240413, which includes a guide piece, is limited to the function of directing the airbag diagonally forward and thus does not meet the above demand.